Unlike the oil carts, a dry herb pen uses flower. They have three advantages over something like a Volcano: theyre a lot cheaper, they dont use bags and they only hold enough weed for one person. There are two basic kinds: ones with temperature control and ones without. Temp control is nice because some weed needs to get hotter to vape properly, but it adds about fifty bucks to the price of the pen. Mine DOESNT have temp control, and it works pretty well. You can save a little money by purchasing a 510-threaded dry herb cartridge and mounting it on a battery for nicotine vaping. Go that way and you get a temp-controlled pen for about the same price as a fixed-temp pen.
You will need the pen, a weed grinder and some weed.
To use: cut a bud in half and grind it fine. It probably wont hold more than that. Take the pen apart in preparation for packing. Next, before you put the weed in the chamber put the mouthpiece in your mouth and try to draw air through it. If its clogged you need to clean out the holes in the compactor plate, and you do so with a toothpick, pin or whatever you have. Once youre getting air through the plate, pack weed into the chamber. Put the pen back together, push down on the mouthpiece to compact the weed against the heating coil, and turn it on. Push the fire button and hold it down while you watch the mouthpiece. When vapor starts to come out, stick it in your mouth and take a hit. When youre finished with this session, take the pen apart, dump out the spent weed, and clean the coil and compactor plate with the little brush they give you.